Hi. I picked up this propeller today and have been trying to figure out what it is. Originally I was thinking airboat but have yet to find one that is rounded on ends (most are square) or one that has 8 bolt holes vs 6. Help?

Bold holes are 3/8in
Propeller shaft is 3 in
Propeller hub is @8.5 in thick top to bottom and 4 in thick.
tip to tip it's 8 feet.

Thanks in advance (I'll try to attach more pics but it would only let me do one)